Actively exploitedCVSS 7.8 · HIGH

CVE-2026-41091

Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.

View on NVD

Analysis

Microsoft Defender contains a vulnerability in link resolution that allows a local user to elevate their privileges. While high severity, this is a standard local privilege escalation bug that is typically handled by automated OS updates and does not represent a systemic risk to developer infrastructure.

Relevant roles

WindowsCyberSecurity

Severity

Score: 7.8(HIGH)

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

AV: LOCAL

AC: LOW

PR: LOW

UI: NONE

S: UNCHANGED

C: HIGH

I: HIGH

A: HIGH

Weakness (CWE): CWE-59

CISA KEV

Added to KEV: 2026-05-20

Federal patch deadline: 2026-06-03

Known ransomware use: Unknown

Required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

EPSS

Probability of exploitation (next 30 days): 0.0655 (6.6%)

Percentile: 91.2%

EPSS: 2026-05-22

Affects

microsoft:malware_protection_engine

Technical description

Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.

Published: 5/20/2026, 1:16:29 PM

Last modified: 5/20/2026, 7:06:36 PM

References

How to read this card

Actively exploited

KEV (Known Exploited Vulnerabilities) is CISA's catalog of CVEs confirmed as actively exploited in the real world. If a CVE is on KEV, someone is already using it in attacks.

CVSS 10.0

CVSS 10.0 — máxima severidad teórica. Explotable de forma remota, sin privilegios, con impacto total. Aún no confirmada como explotada en el mundo real, pero parchea ya.

AI-recommended

Un modelo de lenguaje revisó el CVE y consideró que afecta a software ampliamente desplegado o herramientas comunes de desarrollo. Un humano del equipo aprobó la publicación antes de que llegara aquí.

Categorías de impacto que evalúa la IA

widely_deployed_infra — kernel Linux, OpenSSL, glibc, k8s, Docker, nginx, OpenSSH.

popular_dev_tooling — Node.js, Python, Go, React, Next.js, librerías comunes de npm/pip.

common_consumer_software — Chrome, Firefox, Windows, macOS, apps móviles populares.

enterprise_saas — GitHub, GitLab, Atlassian, Salesforce, Cisco, Fortinet, Ivanti.

niche_software — CMS regionales, herramientas de hobby, librerías de poco uso.

not_relevant — firmware específico de proveedor, software descontinuado.

EPSS — EPSS (Exploit Prediction Scoring System) by FIRST.org estimates the probability that a CVE will be exploited in the next 30 days. Range is 0 to 1; very fresh CVEs typically score low until evidence accumulates.